1. Field of the Invention
The embodiments of the present invention relates to detection of a sync signal in a magnetic recorder, an optical recorder or a similar device.
2. Description of the Prior Art
In the conventional machine for recording and reproducing data from a recording medium, the recording medium is customarily formatted as shown in FIG. 2. In this diagram, SM (sector mark) is a signal representing the top of a sector; VFO SYNC is a clock signal for locking in a PLL circuit; ID is a signal of positional information relative to a track number, a second number and so forth; and SYNC is a signal representing the top of data.
Each track on the recording medium is divided into a predetermined number a of sectors as shown in FIG. 2(a), and each sector is so formated as shown in (b). Such a sector is used as a unitary region when data is recorded. For reading out the data 12 recorded in the sector, a PLL circuit is initially activated by a VFO SYNC 10 recorded in the sector, and a read clock for data 12 is generated. Subsequently, a SYNC signal 11 recorded in the sector is detected in response to a read clock which generates a sync pulse representing the top of data 12, so that the next circuits (demodulation circuit and so forth) to read out data 12 are set. However, in such a conventional read system, some drawbacks exist so that proper demodulation is not attainable when the sync signal is not detected with accuracy, which directly causes an increase of the error rate.